The long term goal is to understand the biological function of carbohydrates on the eucaryotic cell surface through structural, biosynthetic and receptor studies. We plan to gain new knowledge of the structure of a major cell-surface feature of human erythrocytes, "erythroglycan", the large polylactosaminyl oligosaccharide attached to Band 3 glycoprotein. We will concentrate on separation of the mixture of structures within the 7Kda to 12Kda fraction of erythroglycan. Purification of these compounds into several classes of discrete structural types will permit characterization of individual compounds within this group. We plan to use fast atom bombardment mass spectrometry along with conventional carbohydrate sequencing chemistry. Effort will be devoted to development of new techniques in saccharide sequencing. Investigation of the erythroglycans of bovine and porcine erythrocytes will be continued. Biosynthetic studies of polylactosamines will concentrate on purification of the UDP-GlcNAc:Galactose-B-3-transferase from human term placenta, and the "branching" enzyme, UDP-GlcNAc:Galactose-B-6-transferase from murine cells. We will study the specific molecular requirements for the human erythrocyte receptor of Plasmodium falciparum malaria, using purified, chemically characterized fragments of erythroglycan.